As you can tell from my signature I am using a transplanted RC51 SP2 in a unique application. It has been dyno tuned and in general seems to be in great shape.

It was previously running fine for two trips but ran into a problem this weekend. After driving it for somewhere between 5 to 20 minutes it all the suddens just shuts off, especially if going slow during this period. Runs great and maybe even better than it ever has during this time. No popping, no smoke, nothing ... again it really runs great then just shuts down. My temp was getting up to about 215 so thought maybe I just need to run my fan so I hard wired it to a switch. This kept temps to about 175 but still shutting down. Once it shuts down it will start and idle just fine most the time. If I rev it or let out the clutch it shuts down immediately. Sometimes even me just shifting from neutral into first with clutch in it immediately dies. If I let it sit for 10+ minutes it will run just fine until it shuts down. To make it back home I and during troubleshooting had to go through this shutting down, sitting 10 or so minutes, and continuing on about 8 times so it is very repeatable and thus dont think anything electrical etc. is "loose". It really feels like the computer just shuts everything off as no hesitation etc. it just shuts off. No warning lights etc. showing on the digital gauge.

I am running a much bigger radiator than a stock RC51. Checked level and ok. All fluids ok. My power commander powers on and initializes just fine. Any ideas?

I really think this has something to do with something getting too hot and telling it to shut everything down. Could the Power Commander even be doing this?

Could I just be running lean? The custom dyno tune was a safe tune and most of it was increasing fuel. It was done on a very hot 110 degree day (now we are much cooler) and I did switch to the K&N filters afterwards so perhaps this has made it lean?

One other thing I have noticed, but maybe a seperate issue, is when I turn the ignition off it often runs for a few seconds. I only mention this because on one occassion this weekend I turned the ignition off it did not shutdown at all ... left it turned off for maybe 30 seconds and still running so just turned the switch to on and continued. It then shortly shutdown on its own later as discussed above.

Thanks for any help ...

Couple basic questions (some unrelated to this subject):
- What temp is normal and what temp does it shutdown?
- If you start engine with clutch in does it jump forward just a little?
- Anyone running HID lights or alot of accessories and stator have hard time keeping battery charged? I wonder if I need to relocated my voltage regulator to a place where it gets more air rather than behind my seat.

Polaris RZR with an '04 SP2 transplanted in it. Chain driven through a gear box with axles and CVs. The only thing left stock on the RZR is the frame and plastics . But, the frame is beef'd up too .

The fans usually start running around 217-218 deg F.
The critical temp is 251 deg F. When it get that hot, shut it down and let it cool down.
Mine does not jump when started with the clutch disengaged.
If you have a lot of high current devices, it may be possible the charging system may not have the capacity to charge the battery.
The regulator/rectifier would need a little airflow across the cooling fins to keep it cool.

I think the clutch jumping is a different issue. Maybe need to look into adjusting it.

I also think the battery drain issue is seperate. I have a battery voltage monitor it was easily holding 13 to 14.5V during the time I was having the majprity of shutdown issues in daylight then dropped to 11 to 12V at night with all my lights turned on. I think I do need to move the voltage regulator as this was also an issue on this vehicle with stock Polaris motor as it is behind and under the seat with no air flow.

Any more thoughts on what is shutting it down? It was no where near 251F ... 217F is the highest I have seen.

Polaris RZR with an '04 SP2 transplanted in it. Chain driven through a gear box with axles and CVs. The only thing left stock on the RZR is the frame and plastics . But, the frame is beef'd up too .

This might sound ridiculous but could your clutch not be completely disengaging when it gets hot? OR, Could there be something wrong with the ignition switch that is sometimes keeping it running and other times shutting it down?

Well, not exactly ... new Power Commander did exactly the same thing but after only a couple minutes riding. Was about to throw in the towel and then remembered the PC ground wire was attached to the frame when I removed the other one and the install guide called for it to be on the negative battery terminal although I dont think it should matter. Thought it was worth a shot to put it directly on the battery and sure enough no problems on my next three rides. I had even taken the time to clean up the frame ground so know it had clean metal to metal contact but there was also a red mystery wire attached attached to the same place so threw up a red flag and perhaps one way or another it was causing a ground issue.

Polaris RZR with an '04 SP2 transplanted in it. Chain driven through a gear box with axles and CVs. The only thing left stock on the RZR is the frame and plastics . But, the frame is beef'd up too .

After moving the ground, the engine dying after 20 or so minutes completely went away for several weeks/many rides and thought I was done with this. Been in my garage for a couple days with nothing at all done to it, fired right up, let it warm up a little, put it in gear and it instantly dies or if I start it in gear the second the clutch engages it dies. This is one of the side effects of the original issue so I assume a better ground just helped or perhaps soemthing is "frying" my Power Commanders since this is my second one or they are just POS. have no doubt it would run fine without the Power Commander.

Am too frustrated so gonna have someone look at it who has delt a lot with Power Commanders on many street and off road bikes.

Polaris RZR with an '04 SP2 transplanted in it. Chain driven through a gear box with axles and CVs. The only thing left stock on the RZR is the frame and plastics . But, the frame is beef'd up too .

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